Who is the NFL's greatest defensive player of the last 20 years? Tough call. Who is the most controversial? Easy: linebacker Bill Romanowski.

In one of the longest careers in the NFL, Romo, as he was known, played for four teams and led defenses that won four Super Bowls.

This NFL "hitman" earned a nasty reputation for extraordinary violence, breaking bones of his opponents and even a teammate.

In a brutally honest book about a brutal career that correspondent Scott Pelley first reported on last year, Romo admits that he has regrets, steroids, the cheap shots, but he told us there was only one way to survive in the NFL: with overpowering strength and hatred.

"I felt I could take myself to a place where other guys weren't willing to go because come Sunday after a game, I already started hating the next opponent. I started hating the guy I was going to go against," says Romanowski. "I hated the coaches. I hated their fans. I hated their family. You name it. And by the time I got onto that field come Sunday, watch out because there was rage."

Number 53 rode that rage to become one of the most feared linebackers in the NFL.

Nobody goes to the game to watch men play nice, but for Romanowski it wasn't enough to tackle. He aimed to annihilate, to take an opponent out of the game or out for the season.

He hit in a relentless 271 games and never missed one in 16 seasons. An incredible stat, considering the average player hobbles to survive three seasons.

With a name that barely fit on his shoulders, fans called him "Romo" and that is what he became. "To take that field and have every person in that stadium chanting your name, 'Romo! Romo!' How can you not get caught up in that?" says Romanowski.

Who exactly was Romo? "Romo was the hardest working S.O.B. that ever stepped on that field," says Romanowski.

People who despise him don't argue with that. He was known as a fanatic about training, never taking a day off, even in the off season.

But pushing plates was only half the secret. Romanowski had a nearly-religious — some would say weird — devotion to supplements. At home, he had a tackle box of vitamins, minerals, enzymes and amino acids. He took 100 pills a day and made a science of everything from herbs to acupuncture.

He even tried live cell therapy, getting injected with cells from Scottish black sheep. Romanowski says the treatment was supposed to help him heal from the physical trauma he was experiencing on the field.

He spent $200,000 a year on supplements, doctors and therapists and admits he didn't know what was in some of the potions they were pouring.

Romanowski says that in Philadelphia the team sent him to a hospital for something called a Trauma I.V. "When I walked in the hospital on crutches, and I ran out of the hospital, I knew it was something good."

Once, after knee surgery in the off season, he was back in the gym four hours later with anesthesia still drifting through his head.

What was driving him? "A fear of failure. The fear of not being good enough," Romanowski says. "In professional football the competition is so intense. 'Is he good enough? Is he fast enough? Does he hit people hard enough? Does he get hurt a lot?' I didn't want that to happen to me. I didn't want to lose my job."